Abstract

Distributed feedback (DFB) laser arrays are compact and attractive light sources for wave length-division-multiplexed lightwave communication systems and multiwavelength optical networks. Previously, 20-wavelength DFB laser arrays made of bulk active layers have been reported with a 20-nm wavelength span in the 1.5-μm wavelength region.¹ A QW active layer has a broad gain spectrum due to the steplike density of states. A compressive-strained QW active layer has an even broader gain spectrum, because the strong bandfilling effect occurs not only in the conduction band but also in the valence band due to the light-hole-like in-plane hole effective mass.² Recently, we have found experimentally that the threshold current density of tensile-strained SQW lasers decreased with increased tensile strain.³ Moreover, the tensile-strained QW laser has the potential to have narrow linewidth and low chirp because its small linewidth enhancement factor (α = 1.5).⁴ In this work, we report the fabrication and performance of 20-wavelcngth DFB laser arrays with compressive-and tensilestrained QW active layers. The lasing wavelengths span 131 and 56 nm, respectively, in the 1.5-μm wavelength region.

© 1992 Optical Society of America